Backlit displays are used in a number of applications including advertising, entertainment, or informational applications. They are also used in a number of different operating environments including outdoors, direct sunlight, or other applications which may have warm or cool ambient temperatures surrounding the display. Most backlights utilize some form of light guide, which is commonly made of materials which may be affected by changes in temperature. Thermal expansion or contraction of the light guide can cause both mechanical and optical defects in the display.